It is common knowledge that sunburn increases the risk of contracting skin cancer. Sunburn is caused by exposure to two types of radiation emitted by the sun - UVA and UVB. However the Sun Protection Factor (SPF) on sunscreen only measures protection against UVB rays and not UVA rays, which are a major cause of skin wrinkling.
UVA and UVB Protection
When deciding upon sunscreen protection it is advised to choose protection from both UVA and UVB rays. UVA protection is shown by a star rating system - one for the lowest through five for the highest. The higher the SPF number the longer the sunscreen protects against UVB rays. For example, SPF 10 enables the wearer to be protected twice as long as SPF 5.
Guidelines by the World Health Organisation (WHO) advise that sunscreen be applied liberally and at least every two hours. The WHO recommend one bottle of sunscreen per three whole body applications. A very important factor to consider is that sunscreen takes approximately thirty minutes to be effective and therefore must be applied before exposure to the sun.
Care is advised near water as the reflective surface strengthens the harmful effects of the sun and altitude will enhance the burning effect of UV rays. Eye care is important as vision decay and cataracts can result from long term UV exposure, so wearing appropriate sunglasses is essential.
Effects of the Sun
The Sun is a very powerful force with approximately 75% of UV rays penetrating clouds and reflecting off snow, water and sand. UV rays can cause damage to the DNA of the skin. Severe damage can cause normal cells to grow uncontrollably and result in cancer, Melanoma being the most severe form. The speed of skin burning is dependent on skin type of which six types have been identified on The Fitzpatrick Scale.
Skin Type and The Fitzpatrick Scale
In 1975, Thomas Fitzpatrick of Harvard Medical School developed a classification for skin types from very fair to very dark. The system was based on an individual's complexion and response to exposure to the sun. Skin type is determined genetically and is one of the aspects of general appearance including hair and eye colour. Skin reaction to sun exposure is indicative of the skin type of the individual.
The Fitzpatrick Scale is used today to aid healthcare practitioners in the care of patients; for example the success of laser treatments is enhanced by the correct skin typing of the patient.
- Type 1: Highly sun sensitive, always burns and never tans. Example - red hair with freckles
- Type 2: Highly sun sensitive, burns easily and tans poorly. Example - fair skinned, fair haired Caucasians
- Type 3: Sun sensitive, occasionally burns and slowly tans to light brown. Example - darker Caucasians
- Type 4: Minimally sun sensitive, burns minimally and tans to moderate brown. Example - Mediterranean Caucasians
- Type 5: Sun insensitive, rarely burns and tans well. Example - some Hispanics and some Blacks
- Type 6: Sun insensitive, never burns and deeply pigmented. Example - darker Blacks
Protecting Against Sunburn
Time in the sun can be addictive and comforting but treating it with respect is essential to prevent sunburn. Choosing sunscreen with UVA and UVB protection is recommended by health organisations, while being aware of the personal skin type can forewarn of the likelihood of any given individual being susceptible to serious and potentially dangerous sunburn.
References
World Health Organisation
Cancer Research UK
The Times
 |
